Open Source Journeyman

Friday, November 20, 2009

For anyone interested in incorporating dreams and ideas to reality, consider this recently released construction set called MicroRax. MicroRAX is a set of parts that can easily be used to assemble your latest project. It reminds me of the erector sets I used to play with as a child but much more. I wish I had had something as cool as this when I was younger.

The foundation of the kits consists of 6063-T6 aluminum t-slot profiles and nut plates that slide within the slot so that the various joints can be used to connect another profile. Connecting one of joints to the nut plate is done by using the 18-8 stainless steel, M3 x 5mm screws. There are "L" style joints, corner style joints, truss style joints and a 90 degree joining bracket. Getting started is fast and easy. After cutting your profiles to whatever various sizes you might want, the only tool you'll need is the included hex key to tighten down the screws.

I wasn't playing with my free samples very long before ordering the "Pro" kit, which includes 7 90cm profiles and enough of the joints and screws to turn several ideas into reality. A hex key and vinyl caps are also included. I've been working with my kit for almost a week now, trying out the various joints, making boxes, frames and containers. When I'm all done with an idea, I can disassemble it down to the pieces and start over. MicroRax makes it simple to go from idea to project to an actual device quickly and easily. STL files are available at Thingiverse for the profiles to include in CAD programs.I looked through several of the blog posts at MAKE Magazine some of the other maker type sites and see where building my own enclosure for many of the kits available would not only be less expensive but by using frames and enclosures built using MicroRax., when the project has outlasted its usefulness and is sitting in a box in a corner with various electronic parts already removed for newer projects, the mechanical parts can now be disassembled and recycled for my latest idea also.

In the coming weeks, I will be posting some of my assemblies, frames and containers as examples of what the kits can do. The Starter kit runs $89.00 and the Pro kit is $192.00. I am more than happy with the variety and number of parts in the Pro kit and look forward to exploring the possibilities. Stay tuned.

I was not paid or compensated by MicroRAX for this review. While I did receive a free sample, this was not special treatment, as anyone can request the sample.

Saturday, November 14, 2009

One of the interesting topics discussed yesterday during the Digi Webinar is a new product called the SmartPlug. It looks like one of the network extenders or routers. It includes an ambient light sensor but also a switch that allows a light or some other appliance to be plugged into it and controlled. In addition to being able to turn the appliance 'on' and 'off,' it will give a status of the appliance and also the amount of current the appliance is drawing, when 'on.' New drivers have been added to the DIA system so the Smart Plug can be controlled. See the web page above displaying the current, power and the on/off switch.

I ordered two of the Smart Plugs and when they arrive I will try them out and post additional information on them. One of my goals in my project for the house is to be able to control an air conditioning/heating duct and be able to close off one of the bedrooms during the day and force the cooler air to an area of the house that is occupied while having it go back to normal in the evening. The Smart Plug would be great at this as it could not only be controlled manually but have it flip the switch automatically based on a particular temperature or time of the day.

There were other topics discussed during the webinar and I will share those in the next few posts.

Sunday, November 8, 2009

For those of you interested in the iDigi.com XBee controllers and radios, there is a free Webinar on Wednesday, 11 November at 1:00PM - 2:00PM EST. Key Product Focus will be on XBee, ConnectPort X, iDigi Dia, iDigi platform. I will be attending and taking notes.

For the past few weeks I have had some personal health issues that have prevented me from keeping up with my projects, including posting to this blog. Thankfully I have worked through the issues and am feeling better and am catching up with all of my projects. My goal is to start posting and due a minimum of one post per day for the next month, with the possible exception of Thanksgiving Day. I am going through my notes and will either start posting later today or tomorrow. I will also answer any outstanding questions from the comments section. There have been lots of cool things going on over the last few weeks that I haven't been able to participate in but will start jumping in immediately.

Sunday, October 25, 2009

Energy harvesting, according to Wikipedia, "is the process by which energy is derived from external sources (e.g., solar power, thermal energy, wind energy, salinity gradients, and kinetic energy), captured, and stored." So any solar, wind, etc. system that stores energy in batteries or capacitors would be considered an energy harvester. What I am going to focus on are much smaller energy harvesters that can be used to power microControllers, sensors and wireless radios, like the ZigBee types of transceivers.

Assembled energy harvesters, in my opinion, are prohibitively expensive. If you click on any of the Google ads that occasionally appear on this site you will find they run $300-$500, and to purchase a development kit they are over $700. The military is keenly interested in energy harvesters and it seems they are priced for a military budget. For the rest of us, however, there are alternatives.

Basically an energy harvester is nothing more than a source that can collect energy (i.e. solar, wind) and store it for continued use. Both batteries and super capacitors can be used as a storage medium and certain types of DC-DC converters are perfect for this type of use.

Looking at figure 1, the energy collector is a piezoelectric vibration sensor that picks up vibrations and outputs a small AC signal. In its place one could a solar cell, a Peltier Cell or basically anything that can produce an AC or DC voltage, perferably higher than .7 Volts. The four diodes rectify the signal and turn it from AC to DC. In this circuit a Super Capacitor used, with the BZX85-C2V7 diodein place to prevent voltage across the super-cap from increasing beyond the maximum voltage rating.

The controller of the circuit is a Max1675 compact, high-efficiency, step-up DC-DC converters. The important features of the converter is that it will continue to charge a battery or super-cap as long as the voltage is .7 Volts or above and it can be easily configured to output 5 Volts. In the figure 1 circuit, the FB pin is connected to the OUT pin. By connecting the FB pin to GND the output is 5 Volts.In a 5 Volt circuit, the Zener diode would need to be replaced with one that is 5 Volts (TZX5V1B-TAP) and the super-cap would need to be replaced with a higher voltage one or with an appropriate battery.

The Max1675 converter is primarily designed for cell phones, PDAs, pagers, etc. so running at 3.3V & 5V is typical. The package only comes in SMT type so for those of you, like me, that have bifocals it will be tricky to solder.

I recently inquired about receiving a sample from the MicroRAX T-Slot building kit. I was quite surprised to get a call from one of the co-owners of the company, Chris Burrows, who gave me a quick rundown of the company and the products. The kits are a "light weight minature T-Slot building kit" which can be used for engineering mock-ups or any type of maker projects. Once I receive the samples I will post about them and most likely order one of the kits. Stay tuned because I think these kits are something many of us will want as part of our design tool box.

Monday, September 21, 2009

More and more parts are SMD type package only and is just to hard to manually solder, with my old age eyes. Has anyone out there heard of any DIY methods for soldering the SMD type packages to boards? Sparkfun puts out a nice breakout board for 6 pin SOT-23-5 so if there was an easy way to solder the component to the breakout board, it could then be worked with in a normal fashion.